RENTON — When the Seattle Seahawks traded Matt Flynn earlier this month, they didn’t wait long to add depth behind starting quarterback Russell Wilson. Josh Portis, who spent 2011 on Seattle’s roster, and most of last season on the practice squad, was re-signed. Two weeks ago, the Seahawks also added Brady Quinn as a possible backup.

Despite those moves, it’s entirely possible that Wilson’s backup could be someone whose name will be called in this week’s draft, not one of the two players Seattle already has signed.

Yes, Portis has familiarity with Seattle’s offense, as well as the strong arm and athleticism that give him the physical tools needed to run the offense in a similar manner to Wilson. And yes, Quinn is a former first-round pick with starting experience. However, if you’ve learned anything at all about the Seahawks in the past few years, it should be that no presumed role is set, even at the game’s most important position.

If head coach Pete Carroll was willing to let a third-round pick come in and take the starting job from Flynn, you’d better believe he’s willing to let a mid-to-late round pick in this year’s draft wrestle the backup job away from Quinn or Portis. Then add in general manager John Schneider’s belief in the draft-a-quarterback-every-year-regardless-of-need philosophy he learned in Green Bay and the uncertainty at the backup QB spot grows.

Those factors make it not just possible, but rather likely that the Seahawks will use one of their 10 picks this draft on a quarterback, despite having found their quarterback of the future last season.

Although the Seahawks have Wilson to run the offense, they will look long and hard at their quarterback options this week because they know darn well that, as the saying goes, you’re only one play away from needing your backup quarterback. Trading Flynn freed up the cash to make some of the moves Seattle made this offseason, but it also almost certainly left them weaker at the backup QB spot. It was a risk, the Seahawks know that, but one they hope can be mitigated by the addition of Quinn, Portis or a yet-to-be named rookie.

“You sleep really well at night knowing that Matt Flynn is the backup quarterback on your team, there’s no question about it,” Schneider said. “But Brady Quinn has played in this league, he’s a confident guy, and I think he’s going to do a real nice job. And we brought Josh Portis back, so Josh will give it a run as well.”

Schneider also said he wouldn’t mind adding a rookie to that mix, which is hardly a surprise. Although the Seahawks haven’t drafted many quarterbacks since he got here, he says every year that they’re looking to do that if the right player is available. That strategy led to the Packers developing late-round talent behind Brett Favre — Matt Hasselbeck, Mark Brunell and Aaron Brooks, to name a few — that they were able to parlay into future trades.

So who’s out there if the Seahawks, who have no first-round pick this year, are in fact looking for a potential backup in Friday’s or Saturday’s rounds? The player who would fit the mold perfectly behind Wilson is Florida State’s E.J. Manuel and he’ll almost certainly be gone by the time pick No. 56 comes around. Even if Manuel were to last that long, it seems unlikely that the Seahawks would use their first pick on a backup.

The more likely scenario is that the Seahawks will look at a quarterback on the last few rounds, hoping that if all goes well, that player wows them and wins the No. 2 job, or that he at the very least is a developmental project they can stash on the practice squad for a year.

The name most often tied to the Seahawks is Arizona’s Matt Scott, who could be drafted anywhere from the third to the sixth round, depending on the prognosticator. Scott has the athletic ability to run Seattle’s offense, and has a strong, accurate arm. If Scott isn’t there when the Seahawks are ready to draft a backup, they’ll have a few other options, though the later in the draft they go, the more likely it is they’re drafting a third-stringer or a practice squad player, not somebody who is ready to be the backup. Then again, who thought Wilson was ready to start last year? With this team, you never know.

“To me, if they’re going for a dual-threat guy to backup Russell, then there are only a couple of guys who make sense,” said CBSSports.com draft analyst Rom Rang, noting that Manuel will be gone before the Seahawks pick. “Matt Scott from Arizona, he intrigues me. … Zac Dysert from Miami of Ohio, he’s an interesting guy. Not quite as athletic, but he’s a real tough guy. Even (Washington State’s) Jeff Tuel as maybe a seventh-rounder. He’s athletic, he’s got some arm talent to him. As a developmental guy, he’s intriguing. He’s not a superstar, but he was awfully productive on a team that didn’t have a lot of talent around him.”

From hearing Schneider talk about Quinn, raving about his work ethic and saying he “threw the ball extremely well” when the Seahawks worked him out, it seems like the Seahawks would be confident in the former first-round pick as their backup if that’s how things shake out. Seeing Wilson beat out Flynn for the starting job, however, is a reminder that they Seahawks aren’t just going to hand the job to Quinn or Portis without looking at their options this week.

Herald Writer John Boyle: jboyle@heraldnet.com.